Pfeiffer, 55, star of Dangerous Liaisons and Batman Returns, said she became involved with a "very controlling" couple when she was starting out in the film industry. They believed in breatharianism – the ability to live without food and water – and put her on a diet "nobody could adhere to".

But she was "saved" when she was introduced to her first husband, Peter Horton, the actor. He had been cast in a film about the Moonies – the name given to followers of Rev Moon Sun-myung's Unification Church. She said that while she was helping him with research "on this cult" she realised: "I was in one."

"We were talking with an ex-Moonie and he was describing the psychological manipulation and I just clicked," she said in an interview.

Pfeiffer, who left home and moved to Los Angeles when she was 20, described the couple as "kind of personal trainers".

"They worked with weights and put people on diets. Their thing was vegetarianism," she said in the interview ahead of the release of her latest film, The Family.

"They were very controlling. I wasn't living with them but I was there a lot and they were always telling me I needed to come more. I had to pay for all the time I was there, so it was financially very draining.

"They believed that people in their highest state were breatharian," she said.

Followers of breatharianism believe food is unnecessary and sunlight can provide all the nourishment the body needs. However, the practice has attracted criticism and has been linked to several deaths, including that of Verity Linn, 49, who died a remote part of the Scottish Highlands in 1999 after apparently embarking on a period of fasting.

Her diary mentioned the teachings of self-proclaimed prophet Jasmuheen, also known as Ellen Greve, an Australian who preaches that people can draw nourishment from the "divine life force in the form of liquid light".

In the interview, Pfeiffer, now a strict vegan, also denied having plastic surgery, including Botox and fillers, but admitted she found ageing difficult and would "never say never".

"The loss of youth, the loss of beauty – it definitely plays havoc with your psyche," she said.

"There's this transition from, 'Wow, she looks really young for her age', to, 'She looks great for her age'. And there's a big difference. I'm now at, 'She looks great for her age'. There is certainly a mourning process to that.

"I used to think I would never have surgery but it's really hard to say never. I'm in the 'never say never' camp now."

Pfeiffer, who also appeared in The Fabulous Baker Boys, has two children with her husband, David Kelley, 57) a producer. He was the creator of Ally McBeal, the legal comedy drama, and rumours have suggested that Pfeiffer was the inspiration for the neurotic main character. But she scotches such an idea: "No, that's totally made up."

The couple met when they went bowling on a blind date in January 1993 while she was in the process of adopting a daughter, Claudia Rose.